The problem concerns a process for attaching an object to a lightweight material wall with the aid of an insert which features a self-tapping external threading and a cavity for receiving a fastener, and which is turned into a rough hole with the aid of a setting tool engaging the cavity, with a fastener being screwed into the cavity upon removal of the setting tool.
Moreover, the invention relates to a mounting device for the application of the process, with an insert featuring a cavity for receiving a fastener and featuring a self-tapping external threading, and with a setting tool engaging in rotationally fixed fashion the cavity of the insert.
Processes and devices of that type are known from DE-C3-22 56 938 and DE-C2-24 19 111, the insert being closed on the front end and, upon creation of a cylindrical rough hole, turned into the latter with the aid of a power drill. As the insert is screwed into the cylindrical rough hole, its external threading cuts itself into the soft lightweight construction material, leaving the material between threads intact. This enables an anchoring free of expansion pressure, of a fastener which upon setting of the insert is screwed into its axial cavity for mounting an object.
EP-B1-165-674 describes an insert featuring on the insertion end an opening and a drill blade protruding beyond the insertion end of the insert provided with a self-tapping external threading. The drill blade makes it possible to dispense with creating a cylindrical rough hole, since it is produced in a lightweight construction material during the setting, with the aid of the drill blade arranged on the front end of the insert sleeve. As a fastener used as a screw is turned in upon setting the insert in a lightweight construction material with a material thickness smaller than the length of the insert provided with the external threading, the front end of the screw forces the drill blade sideways out of the way. Therefore, the prior insert not requiring a rough hole can be used only if its length exceeds the thickness of the lightweight construction material. An application involving merely a blind hole, and not a through-hole, is not possible because of the necessary sideways escape movement of the drill blade.
Basing on this prior art, the problem underlying the invention is to provide a process and device of the initially discussed type which in a material-saving way allow a quick and simple assembly in lightweight construction materials without preparing a rough hole.